Cardiovascular complications are primarily responsible for the high morbidity and mortality in people with stroke and diabetes mellitus (DM). Cardiovascular diseases are roughly three times higher in patients with neurological deficits than in patients without neurological diseases. DM is a prominent risk factor for cardiovascular diseases and cerebral ischemic stroke. Our preliminary data show that ischemic stroke and type two DM (T2DM) each induces cardiac dysfunction, while T2DM animals subjected to ischemic stroke exhibit profound cardiac dysfunction compared to non-stroke T2DM mice or non-T2DM stroke mice. Therefore, there is a compelling need to develop therapeutic approaches specifically designed not only to reduce neurological deficits, but also to decrease cardiac dysfunction after stroke with diabetes. Our preliminary data indicate that treatment of stroke in T2DM mice with exosomes derived from human umbilical cord blood isolated CD133+/KDR+ cells (CD133+Exo) 3 days after stroke not only improves neurological and cognitive outcome, but also significantly improves cardiac function and increases heart microRNA (miR)126 and miR29b expression. In a novel and clinically relevant approach, based on our robust preliminary data, we propose to investigate the underlying cardioprotective therapeutic mechanisms of CD133+Exo treatment of stroke in T2DM mice, and we will test the hypothesis that miR126 and miR29b mediate CD133+Exo-induced cardiac protective effects in male and female mice in vitro and in vivo. Two Aims are proposed. Aim 1: To investigate the effect of cerebral ischemic stroke and stroke-related factors (age, sex and T2DM) on cardiac and neurological function in mice. To test the therapeutic effects of CD133+Exo treatment of T2DM-stroke in male, female and aged mice, time window, dose response, multiple doses and combination with anti-diabetic drug (Metformin) studies will be performed. Aim 2: To investigate the mechanism of CD133+Exo induced cardiac protective effects in male and female T2DM-stroke mice in vitro and in vivo. We will focus on miR126 and miR29b, and will test: 1) whether CD133+Exo treatment of T2DM-stroke increases heart and serum miR126 or miR29b levels; 2) whether increasing miR126 or/and miR29b expression in heart or/and serum mediates the CD133+Exo induced cardiac beneficial effects in male and female T2DM-stroke mice; 3) whether the miR126/Spred-1 and/or the miR29b/DPP4 signaling pathways mediate CD133+Exo treatment induced myocardiocyte protection of cultured cardiomyocytes. A major significance of our investigations is that it opens up important and novel ways to understand how exogenously administered CD133+Exo communicate with and alter heart cells by means of miR delivery to thereby activate endogenous cardiac protective events. This proposal is highly clinically relevant and if successful, it will significantly impact the treatment of stroke, diabetes, and cardiac dysfunction. Importantly, this proposal will elucidate novel mechanisms of action and generate therapeutic targets for CD133+Exo treatment of cardiac dysfunction after stroke with T2DM in male, female and aged mice.